Grinding machine



Dec. 14, 1926. I F. c. SANFORD GRINDING MACHINE Filed 24, 1.922 5 Sheets-Sheet 1 10 I Dem 14,- F c.sANF0RD GRINDING MACHINE Filed August 1922 5 Sheets-Sht 2 Dec. 14, 1926. i

. F. C. SANFORD GRINDING MACHINE "O t e e h S t e e h s 5 Filed August 24 1922 5 Sheets-Sheet fil dizzaz F. c. SANFORD GRINDING MACHINE Filed August 24,

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Dec. 14, 1926. 7 ,611,135 F. c. SANFORD GRINDING MACHINE Filed August 24. 1922 5 Sheets-Sheet 5 jhuenior Patented Dec. 14, 1 926.

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'FRANCIS C. SANFORD, OF BRIDGEPOR'I', CONNECTICUT, ASSIGNOR TO THE CINCINNATI MILLING MACHINE COMPANY, OF CINCINNATI, OHIO, A CORPORATION OF OHIO.

GRINDING MACHINE.

Application filed August v.24, 1922.

. ation, capable of producing various bodies,

whether-cylindrical or tapered, of predetermined dimensions, of true circular cross section, and with straight and true surfaces from end to end.

These objects are attained by the construction illustrated in the accompanying drawings which show one embodimentof the invention, but it is to be understood that variations of the structure may be made within the scope of the invention and as may be required'or suggested by different conditions and uses. l

In the drawings-- Figure 1 is a broken plan View of the machine with the guards of the .grinding and the second wheel removed. I

'Figure 2 is an elevation of the machine partly in section at the line 2-2 of Figure 1,-and broken away. I I

Figure 3 is a detail perspective view, partly broken away, of the assembled slides and- .parts carried thereby. t

Figure 4a detail perspective view of the work rest preparatory to assembly. a

Figure 5 a detail perspective view of the members by which the blanks or objects ground are moved over the active surface of the grinding wheel.

- Figure 6 a detail elevation, partly broken away, showing the push or thrust fingers of said members. in proper position relative to a blank to be ground with the latter supported on the work rest.

Figure 7 is a view similar to Figure 6,

' but omitting the work. rest and showing said fingers provided with conical points to enter seats or depressions formed in the ends of the blank. Y 5

Figures 8 and 9 re views similar to Figure 6, but showing more particularly how the thrust fingers are utilized to position the blank or work along theiincline of the work rest in grinding tapered'bl'anks.

Figure 10 is a detail broken plan view showing the position of parts when the blank Serial No. 583,969.

the grinding wheel. a

Figure 11 is a section at line 1111 of Figure 1, and showing more particularlythe relative positionsof the work guide guards, the thrust fingers and work rest with respect to the blank.

Figure 12 is a detail broken plan view showing the position of parts immediately after a blank has, been delivered in proper position between the thrust fingers, and

Figure 13 is a broken plan view showing a modified form of my invention in which the swinging carriage is omitted and the second wheel journaled directly upon the secondary slide. 1

Similar numerals of reference denote like parts in the several figures of the drawing.

In'centerless grinders in which the blank is operated upon by the peripheral surfaces of a grinding and a secondary wheel on opposite sides of the work, the axes of thetwo wheels are usually placed and maintained in parallel planes which are commonly vertical; but in the present machine provision is made for bringing the plane of the axis of the secondary wheel into or carrying it out of parallelism with that of the grinding wheel axis, depending upon whether it be desired to grind to true'cylindrical or to tapered or conical form. If the conical form is desired the angular relation of the axes is made to correspond with the desired angularity or degree of taper of the finished product, but for cylindrical grinding the axes are maintained in parallel planes. The periphery of the secondary wheel is spaced from the periphery of the grinding wheel a distance determined bythe diameter or diameter and taper which-it is desired to give to the finished work. The work is introduced longitudinally between the peripheries of the grinding and second wheels from either side, or alternately from opposite sides.

The speeds of the grinding wheel and the second wheel "may be varied as desired by the employment of. driving and driven pul sizes, and this. will depend in greater or less degree upon the nature of the material operatednpon. In thisi'machine provision is made vfor'advancing or' axially moving the blank or work by means independent of or bodies of circular cross section, Whether plain or tapered, and that it is immaterial whether these surfaces are identified with roller bearings or not.

1 is the bed of the machine having dovetailed ways 2, extending lengthwise of the same on which is arranged the primary slide 4 is' the secondary slide which operates on dovetailed bearings a transversely dis-- posed at the rear or inner end of the slide 3, so that it will be readilyunderstood that the latter carries the slide 4, while the slide 4 itself may be reciprocated in a direction transverse to that in which the slide'3 moves.

J ournaled on the slide 3 is a horizontally disposed worm wheel 5 which meshes with a worm 6 also journaledon theslide 3 and having its shaft 7 provided with a suitable pulley wheel 8, Fig. 1, which latter is operated in the manner hereinafter to be described.

9 is alink bar or lever having an elongated slot 10, the outer end of which bar is pivoted at 11 to'the slide 3 while the inner end of the bar is pivotally connected to the slide 4 by means of a stud 12 which extends through an elongated slot 13 in the bar, this kind of pivotal connection being. well known and being utilized to prevent binding at the piv- .otal point.

Extending eccentrically from the face of the worm wheel 5 is a stud 14 which passes loosely through a block 15 which latter extends up within the slot 10.

As the-worm wheel 5 is rotated owing to its connection with the worm 6. the rotary travel of the eccentric stud 12 will effectan oscillation or swinging movement of the bar 9, and'this will cause a longitudinal recip rocation'of the slide 4 transversely. of the slide 3. This movement just described is a well known mechanicalone and will apparently require no further description.

The worm wheel and worm and bar are protected from dirt and other foreign matter by means of a cover 16 which is secured to the slide 3., and to the outer end of this cover is fastened a screw shaft 17, which has a threaded engagementwith a nut 18 which latter is swiveled within a bearing support 19 that is secured. to the bed plate, and rigidly .secured to this nut is an operating hand wheel 20.

The inner end of the nut 18 is radially flanged, and-the-hub of the hand-wheel 20 is bf larger diameter than the body of the nut, and when secured upon the outer .end

primary slide 3,

and 2.

thereof forms a shoulder which, with the radial flange, precludes endwise movement of the nut. Rotation of the hand-wheel in thereby. This adjustment is for the purpose of determining the distance between the peripheral faces of the wheels through which the grinding is effected. I

Pivoted at 21 upon the sTide 4 as shown in Fig. 3, is a carriage 22 at the ends of whichare curved elongated slots 23 through which extend bolts 24 that have threaded connection with the slide 4, the object of these slots and bolts being to secure the carriage 22 in any of the adjustments to which it is swung.

25 are ways secured to or formed upon the upper surface of the carriage 22,-and 26 is a bearing block slidable on said ways and having at each end a slot 27 with a bolt 28 passed thercthrough and screwed into the carriage for the purpose of securing the block in its adjusted positions.

29 are the bearings for the shaft 30 of what will hereinafter be referred to as the second wheel 31 these bearings being secured to. the block 26 by bolts 32, as seen in Figs. 1, 2 and 13.

33 is the grinding wheel 'the shaft 34 of which is journaled within bearings 35 that are secured directly to the bed plate 1, and

on this shaft is the usual power pulley 36, for connection with motive power.

Al'so secured upon the shaft 34 is a pulley 38 which connects with the pulley wheel S by means of any suitable belt 39, and an ordinaryslack-taker 40 is arranged at the side of the bed 1 for taking up the slack in the belt 39 incident to the movements of the all as shown in Figs. 1

The rotationof the secondary wheel Ell/is controlled by means of, any suitable belt (not shown) ar'ouud the power pulley. 41, 'on the shaft 30, and in this connection at tention is called to the fact that the speed of the grinding wheel 33 is much greater than that of the second wheel 31. As seen in Figs. 1, 2. 10. 12 and 13, 43 is the work rest block which has a stud 44 projecting from the lower face and seated within an orifice 45 in thecarriage 22, so that it will be clear that this block is capable of swinging movements. and at the ends of the block are curved slots 46 through: whichbolts 47 excurved concentrically with the pivot 48, through which slots extend bolts 51 entering tapped holes in the face of block 43, said bolts serving to clamp and hold the work-rest in any position to which, it may be tilted upon or about said pivot 48.

This rest is located immediately below the space which separates the grinding wheel and the second wheel, and the blanks to be ground are delivered "directly upon the rest in' the manner hereinafter to be described.

Since in the-present structure the second wheel isin no sense a feed wheel, because it does not feed the work to be ground transversely across the face of the grinding wheel, means are provided whereby such axial travel of the blank is effected and this means will now be described.

52 are push fingers having outwardly extending tails 53 and bases 54 which latter are secured directly upon and to the slide 4 by means of bolts 55 passing through elongated slots 56 in saidbases and entering tapped holes in the slide 4, as seen in Figs. 1 and 2 and 10 to 12. It will thus be clear that these fingers may be spaced apart more or less by means of the adjustment afforded by said slots and bolts.

The blanks to be ground are delivered upon the work rest 49 between these fingers 52 the latter having been previously adjusted to accommodate the lengthof said blanks,

and since said rest and fingers are bodily so that its peripheral face will conform to carried by the slide 4 it will be clear that the blanks will be pushed bodily endwise by means of these fingers during the traversing .movements of said slide, and in this connection attention is called to the fact that these fingers are always substantially in line with the work rest.

The machine illustrated in the drawing is equipped for grinding a blank at each transverse movement of the slide 4, and is therefore provided with two chutes 57 and 58, for delivering the blanks to be ground, these chutes being located on opposite sides of the grinding wheel and being spaced therefrom. (See Figsnl, 10, 12 and 13.)

During the reciprocation of the slide 4 the space between the fingers 52- will be brought directly opposite the delivery mouth of one of the chutes, whereupon a blank will pass from the chute into this space and upon the work rest 49, and just as soon as the reverse movement of said slide begins one of the tail extensions 53 will block the chute. As the blank thus delivered between the push fingers comes opposite the space between the chute and the grinding wheel there is danger that said blank might become dislodged or fail to be properly delivered to the grinding wheel, and therefore guide guards 59 are provided on each side of the grinding wheel, said guards being adjustably mounted on pillars 6O that are secured to the slide 3. The adjustment .of-these guards is merely for the purpose of accommodating them to difterent sizes of blanks to be ground, such adjustmentbeing accomplished by means of I ly below the axis of the blanks to be ground,

while the adjustment of the rest is for the purpose of bringing the axis of the blank below the horizontal plane of the axis of the grinding wheel, and maintaining said axes in parallelism. While I have referred to such adjustment of the work-rest as shall cause the axis of the'work to be below the horizontal plane of the grinding wheel axis, I do not intend to restrict myself to such adj u'stment, it being advantageous under some circumstances to have the axis of the work in the same horizontal plane as the axis of the grinding wheel, or above such plane.

\Vhen the carriage 22 is swung about its pivot 21 it, of course, carries with it the. work-rest 49, and the latter may not under such adjustment stand immediately below the axis of the blank to be ground. In such case the block 43 will be separately adjusted to give said rest proper relative'po'sition. When the blanks to be ground are tapered, it is necessary to adjust the second Wheel 31 the angle of the taper of the blanks, and this is brought about by the 'swin' ing adjustment of the carriage 22. Accor ingly it becomes necessary to make a nice adjustment of the wheel 31 so that its peripheral surface will very closely conform to this taperand this adjustment is effected by the inward sliding" movements of the block 26 which carries the journals .of the shaft of the wheel 31. The "primary slide 3 is adjustable by means of the operation of the handle 20 both to compensate for wear onthe grinding and second wheels and for blanks of different cross diameters. I The operation of the machine, when provided with two delivery chutes, so that a blank may be ground at each transverse movement of the second wheel, is as follows r Presupposing the parts to be in the position shown at Figure 12, it will be observed that the space between the fingers 52 is opposite a delivery chute 57, and that a blank has moved from this chute to a position between the fingers and against the second wheel 31.

llii

Theblank thus delivered is supported immediately by the work rest 49, as shown at I blank in chute 58 until the blank so ground passes completely beyond said chute and falls 01f the work-rest on the side of the 'rest away from wheel 31. Upon reversal of movement of the secondary slide 4 the space between the fingers 52 Wlll again .be brought opposite the delivery end of chute 58, where- 7 upon the foremost blank therein will enter the space between said fingers and come into surface contact with the periphery of the wheel 31.' Further movement of slide 4 will cause the fingers 52 to move the fresh blank transversely across the peripheral face of the grinding wheel 33, and-past'the delivery end of chute 57 to a point where said blank will fall from the work-rest just prior to another reversal of movement of slide 4. These operations are repeated as the slide 4 is traversed first in one and then in the opposite direction.

It will be observed that intermediate the grinding wheel and the-chutes are provided the guide guards -9 which project upwardly and are in line with the peripheral face of the grinding wheel, so that these guards prevent the blanks from toppling off the'work rest and also insure their delivery against the face of the grinding wheel.

It will, of'course. be obvious that the two chutes are not at all necessary. and that one of them may be omitted. in which case, one

of the guide guards and one of the fingers would be omitted, but since the machine has I a far greater output when two chutes are employed it is preferred that the machine be constructed as shown in the drawing.

If the blanks be plain cylindrical bodies withno tapered surfaces the second wheel 31 1s so adjusted that its peripheral face will be parallelto the peripheral face of the grinding wheel, the operation of the machine being precisely the same whether the blanksare tapered or not.

The mechanism heretofore described for operating the primary and secondary slides is quite ordinary, and since these slides may be operated in various ways, all of which are ordinary shop ,expedients, I do not wish to be limited to the employment of any particular mechanism for operating these slides.

In grinding tapered blanks'the angular adjustment of the peripheral face of the second wheel is always such that whena tapered blank is in contact with said wheel and is properly supported on the work rest between the fingers, such blank will always present to the peripheral faceof the grind- .line across the same in parallelism of the grinding wheel,

ing wheel a surface that extends in a straight axis of the grinding wheel.

In grinding rolls for roller bearings it is deemed desirable that the axes of such rolls should be slightly below the axis of the grinding wheel, but that the two axes should be parallel, and this IS a very simple with the matter to provide for in the grinding of plain cylindrical roller bearings, since the work rest is merely adjusted to the proper I horizontal plane. But in the-grinding of rolls or blanks with tapered surfaces, the present invention is particularly well, adapted for properly positioning the work, since itis merely necessary to adjust the fingers 52 so that they will normally position the blank at various locations along the inclined upper surface of the work rest as clearly shown at Figures 8 and 9, where it will be noted thatthe axis of the blank is always in a horizontal plane, and therefor parallel with the axis of the grinding wheel, whether the blank he at the depressed or at the elevated end of the work-rest or at any intermediate point. The elevation of the plane of the axis of the blank will, however, vary as the blank is placed nearer the lower or the higher end of the work-rest. When the fingers 52 are adjusted to bring the work to the desired point in the length of the work-rest and are clamped in such adjustment, the fingers and the work-rest move together, and the blank retains a fixed position upon the rest during the traverse and grinding of the blank.

I have shown, as the preferred embodiment of my invention, and have heretofore described, the second wheel as mounted on a carriage capable of swinging adjustments,

so as to present the peripheral face of said wheel at an angle to the corresponding face On referrlng to Figure 13 it will be seen that the carriage- 22 may be dispensed with and the second wheel journaled in bearings that are supported directly upon the secondary slide 4, the peripheral face of this second wheel being itself beveled so as to correspond with the angular surface to'be ground.

In this Figure 13, the work rest block 43 and the block 26 are supported directly upon the secondary slide 4, and the adjustments of said blocks are identical with those heretofore described in connection with these blocks. The peripheral face of the second wheel is dressed at the desired angle by the usual diamond tool, and the operation of the machine, with the swinging carriage thus omitted, is precisely the same as has been hereinbefore described.

It is obvious that the construction illustrated inFig. 13 and just described may be used in the grinding of cylindrical rolls or two wheels 31 and 33.

riphery shall beparallel with that of the grinding wheel 33 and with the axes of the The drawings and accompanying description thereof are based upon the preferred construction and arrangement of parts,

' wherein the axes of the grinding wheel 33 and claims are to be read with this and second wheel 31 are in a common horizontal plane, and in stating that the axis of the blank orwork is maintained below the axis of the grinding wheel, the word .below is used with reference to such relative positions of the wheel axes. A like rel tion of the work axis to the common plane of the wheel axes will usually be maintained, whether such plans be horizontal or inclined from the horizontal, and the specification understanding.

Having thus described my invention what is claimed is I 1. In a machine of the character described, the combination of a grinding wheel; a second wheel adjustable to bring its peri heral face at will into angular or into 'paral el relation to the peripheral face of the grinding wheel; a work-rest; and means for'traversing one of said'wheels and work-rest with a blank upon it, transversely across the peripheral face of the other of said wheels inv the direction of the axis of the blank;

2. In a machine of the character described, the combination of a grinding-wheel; a second wheel having its peripheral face ar ranged in angular relation to the peripheral face of the grinding wheel; a work-rest; and means for traversing the second wheel and the work-rest with a blankhpon it, transversely across the peripheral faces of the grinding wheel in the direction of the axis of the blank.

3. A machine of the character described, comprising a grinding wheel, a second wheel capable of adjustment to bring its peripheral face at an angle to the peripheral face of the grinding wheel, means for delivering blanks to said wheels, and means for bodily carrying said blanks and second wheel axial- 1y .across ,the peripheral face of the grinding wheel.

4. A machine of the character described, comprising a grinding wheel: a second wheel adjustable to place its peripheral face at any desired angle to the corresponding face of the grinding wheel; means for feeding blanks to'said wheels; and means for bodily carrying said blanks and second wheel transversely of the grinding wheel, to a point, at which the blank is freed and discharged.

5. In a machine of the character described comprising a grinding wheel and a second wheel adjustable to place its peripheral face at any desired angle to the corresponding face of the grinding wheel; means for bodily moving the second wheel toward or away fromthe gr'inding wheel to vary the space between said wheels; means for feeding and delivering blanks to and from said wheels;

and means for bodily carrying said blanks and second wheel axially across the grinding wheel.

6. A machine of the character described comprising a grinding wheel, a second wheel adjustable to place its peripheral face at an angle to the peripheral face of the grinding wheel in the common plane of the wheel axes, and means for introducing, feeding, guiding and carrying a blank from one side of the grinding wheel to the other.

7. A machine of the character described, comprising agrinding wheel carried in stationary bearings, a second wheel peripherally opposed to the periphery of the grinding wheel and journaled in bearings adjustable 1n the common plane of the wheel axes to place its periphery at an angle to the periphcry of the grinding wheel, a work support betWeen'said wheels and movable in harmony with said swinging bearings, means for delivering ablank to the work support, and means for bodily shifting said second Wheel and the work support with a blank upon it transversely across the peripheral face of the grinding wheel, in the direction of the axis of the blank.

8. In a machine of th character described, a grinding wheel and a second wheel peripherally opposed thereto, means for adjusting the second wheel in the common plane of the wheel axes to position its peripheral face at an angle to the corresponding face of the grinding wheel, a support for the work,

means for feeding the work upon said support, and means for causing said support and second wheel to move across the peripheral face of the grinding wheel in the direction of the axis of the work.

9. In a machine of the character described, a grinding wheel and a second wheel peripherally opposedvthereto, means for adjusting the second wheel in the common plane of the wheel axes to position its peripheral face at an angle to the corre ponding face of the grinding wheel, a work support, means for delivering work thereto, conveyor fingers for embracing the work at each end thereof. guide-guards adjacent-the grinding wheel, and means forcausing the second wheel, the work support and the conveyor fingers to more across and "beyond the peripheral face of the grinding wheel, in the direction of the axis of the worln 10. In a .machine of the character dc-, scribed, a grinding wheel and a second'wheel peripherally opposed thereto, means for adjusting the second wheel. in the common plane of the wheel axes to position its peripheral face at an angle to the corresponding face of the grinding wheel. a chute for feeding the work, a guide guard located betweenthe grindingwheel and the chute,

a support onto which the work is fed, conveyor fingers for embracing the work at each end thereof, said fingers having tail extensions which block the chute at all times except when the spacc'betweensaid fingers is alined with said chute, and means for causing the second wheel, the work support and the conveyor fingers to move acrois the peripheral face of the grinding wheel, and to carry the space between the fingers to and beyond the chute.

. 11. A machine of the character described comprising a bed, a grinding wheel journaled thereon, a primary slide on said bed movable toward and away from said wheel,

a secondaryslidecarried by the primary Slide and movable transversely thereof, a second wheel carried by thesecondary slide, and adjustable in thecommon plane of the wheel axes to present its peripheral face at I an angle to the peripheral face of the grinding wheel.

12. A machine of the character described,

fingers, and means for reciprocating said secondary slide and the parts carried thereby transversely across the peripheralface of the grinding wheel, in the direction of the axis of the work;

13. The combination with a grinding wheel, of a second wheel in plane with the grinding wheel, having its peripheral face set an angle to the opposing face of the grinding wheel; means for holding a blank against the face of the second wheel; and means for carrying the. second wheel and the blank so held axially across the peripheral face of the grinding wheel and in contact therewith.

14. A machine of the character described, comprising a bed, a grinding wheel having its shaftjournaled in bearings carried by said bed, a primary slide adapted for travel on said bed and lengthwise thereof, a secondary slide adapted for travel on the primary slide and transversely thereof, a carriage pivoted on the secondary slide, a second wheel whose shaft is supported on said carriage, said wheel having its peripheral face opposed to the peripheral face of the grinding wheel, means for adjusting said carriage to place the peripheral face of the second wheel in desired angular relation to the peripheral face of the grinding wheel,

block the blank delivery means at all times except when the space between the fingers 1s brought ()PPOSltO said delivery means, and means for operating the secondary slide, whereby the blank on the work rest, I

backed by the second wheel, is carried by the lingers across the face of the grinding wheel in close contact therewith.

' 15. A machine for grinding tapered blanks, comprising in its organization a grinding wheel and a second wheel, the peripheral faces of the two wheels being opposed; means for adjusting the axis of the axes of the two wheels, whereby their 'rpposed peripheral faces are placed in angular relation one to the other; means for supporting between the opposed peripheral faces a blank to be ground; means for delivering blanks onto said support; means co-operating with said second wheel for holding a blank during the grinding; and means for bodily carrying said blank, support, and second wheel across the peripheral face of the grinding wheel with the blank in grinding contact with said face.

16. A machine for grinding bodies of circular cross section, comprising a bed, a grinding wheel journaled in bearings supported on said bed, a second wheel'having its peripheral face opposed to the corresponding face'of the grinding wheel, a movable carriage which supports the journals of the second wheel whereby the latter is bodily carried transversely across the active face of the grinding wheel, a work rest carried by said carriage in close, proximity to the face of the second wheel, means for delivering blanks onto said rest and against the face of the second wheel, means for second wheel in the common plane of the guiding the blanks, and means for actuatmg said carriage to carry the second wheel, the work rest and the blank supported thereby axially across the face of'and in grinding contact with-the grinding wheel.

means for guiding said blank axially in its movement to;across and from the grinding wheel.

' 18. In combination with a grinding wheel and a second wheel placed v in peripheral opposition, the proximate peripheral faces being at an angle one to the other; a tiltable work-rest; and a support-upon which said work-rest is pivoted. said'support being capable of adjustment to bring the work-rest directly beneath and parallel with the axis of a blank placed thereon, and

i the tilting work-rest serving when properly -adjusted to support and maintain the blank with itsaxis parallel to, the axis of the grinding wheel, I

19. The combination of, the grinding Wheel, a vertically disposed work rest capable of swinging adjustments whereby its up per edge may so support the blank to be ground that the axis of the latter isbelow and parallel to the' axis of the grinding wheel, means for holding said blank so that its side surfaces will always be presented to the peripheral face of the grinding wheel in contact therewith in a straight line that is. parallel" to the axis of said wheel, and means for causing the blank thus held to traverse said face, in the direction of the 20. In a machine of the character described, the combination of a grinding wheel,

a second wheel, meansv for Spacing said wheels apart more on less, means for swing: ing the axis of the second wheel in the common plane of the axes" of the two wheels whereby its peripheral face is presented at an angle to the corresponding face of the grinding wheel; a vertical work rest located close to the periphery of the second wheel and adjustable in a horizontal plane whereby said rest will-be parallel with the axis of the blank thereon, said rest also having swinging adjustments in a vertical plane whereby the axis of the blank supported thereon will always be below and parallel to the axis of the grinding wheel, means for delivering the blanks onto said rest and against the peripheral ,face of the second wheel, means for guiding the blanks, and means for carrying said blanks thus supported across and in grinding contact with the peripheral face of the grinding wheel.

21. In a machine for grinding bodies .of circular cross section, the combination of a grinding wheel; a second wheel peripherally opposed thereto; a rest for supporting a blank between. the, proximate peripheral faces of said wheels; means for delivering a blank onto said rest and holding it against said second wheel; and incansifor'earrying the second wheel, work rest and blank axially athwart the peripheral face of the grinding wheel. and in grinding contact therewith.

22. The combination with a grinding wheel, of a second wheel whose peripheral ond wheel having their peripheral surfaces" opposed; a reciprocating carriage on which the second wheel is mounted and with which it moves; a work-rest or support intermediate the opposed faces of the two wheels,

carried by and movable with said carriage;

fingers at opposite ends of the work-rest and 111 substant al ahnement therewith, said fingers being movable with the carriage and serving positively to advance a blanklying upon the work-rest and carry t across the peripheral face of thehgrinder as the carriage moves in either-direction; tails or extensions in plane with said fingers and extending in a direction opposite thereto; and chutes, one on either side of the grinding wheel, each serving to delivera blank to the work-rest when the spacebetween the fingers registers with the discharge end of either of said chutes, the tails or extensions serving to close the delivery ends of the chutes except at such times as escape of blanks therefrom is prevented by the blank at the moment being introduced or'being carriedfroin the grinding position to the point of discharge. i 1

24. In a centerless grinding machine, the combination of a grinding wheel and a second wheel having their peripheral surfaces opposed,the peripheral surface of the second wheel being at an angle to the proximate surface of the grinding wheel; a reciprocating carriage on which the second wheel is mounted and with which it moves; awork- Ill-l rest or support intermediate the opposed- I faces of the two wheels, carried by and movable with said carriage; fingers at opposite ends of the work-rest and in substantial alinement therewith, said fingers beingmovable with the carriage and serving positively to advance a blank lying upon the work-rest between the fingers registers with the dis charge end of either'of said chutes, the tails or extensions serving to closethe delivery is mounted for rotation; a work-rest; fingers provided with longitudinal extensions and in substantial alinement with the work-rest,

' said fingers being adjustably'spaced apart to permit the introduction between them of a blank to be ground; chutes on opposite sides of the active peripheral face of the grinding wheel, for delivering blanks one at a time onto the work-rest and between hereto.-

the fingers guards fixed on opposite sides of the grinding wheel between the same and the proximate chutes; means for moving thecarriage. second wheel, work-rest and fingers back and forth across the active face of the grinding wheel and past the guards; and means for rotating said wheels in proper direction and at suitable speed; whereby a blank is positioned upon the work-rest at one side of the grinding wheel, carried across and 'ground by the grinding face, and moved to a point beyond the guard and chute at which it is discharged from the work-rest, this act-ionoccurring at each movement of the carriage in either direction. I

In testimony whereof I aflix my signature FRANCIS C. SANFORD. 

